Determination of moisture content and basic specific gravity of Populus tremuloides (Michx.) and Populus balsamifera (L.) logs using a portable near-infrared spectrometer     

Guillaume Hans  Brigitte Leblon  Paul Cooper  Armand La Rocque  Joseph Nader 《Wood material science & engineering》2015,10(1):3-16

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Photoinhibition of photosynthesis in needles of two cypress (Cupressus sempervirens) clones     

La Porta N  Bertamini M  Nedunchezhian N  Raddi P  Muthuchelian K 《Tree physiology》2005,25(8):1033-1039

Photoinhibition of photosynthesis and photosynthetic recovery were studied in detached needles of cypress (Cupressus sempervirens L.) Clones 52 and 30 under controlled conditions of high irradiation (about 1900 micromol m(-2) s(-1) for 60 min; HL treatment), followed by 60 min in darkness. The degree of photoinhibition was determined based on the ratio of variable to maximum chlorophyll fluorescence (Fv/Fm), which is a measure of the potential efficiency of photosystem II (PSII), and on electron transport measurements. The Fv/Fm ratio declined in needles of both clones in response to the HL treatment. Minimal fluorescence (Fo) increased in HL-treated needles of both clones. The HL treatment decreased rates of whole-chain and PSII activity of isolated thylakoids more in Clone 52 than in Clone 30. In needles of both clones, PSI activity was less sensitive to photoinhibition than PSII activity. In the subsequent 60-min dark incubation, fast recovery was observed in needles of both clones, with PSII efficiencies reaching similar values to those in non-photoinhibited needles. The artificial exogenous electron donors diphenyl carbazide (DPC), hydroxylamine (NH2OH) and manganese chloride (MnCl2) failed to restore the HL-induced loss of PSII activity in needles of Clone 30, whereas DPC and NH2OH significantly restored PSII activity in photoinhibited needles of Clone 52. Quantification of the PSII reaction center protein D1 and the 33-kDa protein of the water-splitting complex following HL treatment of needles revealed pronounced differences between Clone 52 and Clone 30. The large decrease in PSII activity in HL-treated needles was caused by the marked loss of D1 protein and 33-kDa protein in Clone 30 and Clone 52, respectively.  相似文献   

桉木与杨木阻燃胶合板的性能对比分析     

胡拉  陈志林  傅峰 《木材工业》2015,29(3)

采用磷氮硼复合阻燃剂浸渍处理桉木和杨木单板,分别制备5层阻燃胶合板,检测其物理力学性能和阻燃性能.结果表明:阻燃胶合板的胶合强度,均满足GB/T 9846-2004《胶合板》中Ⅱ类要求,抗弯性能满足LY/T 1738-2008《实木复合地板用胶合板》要求;两树种胶合板相比,杨木阻燃胶合板的胶合强度较好,桉木阻燃胶合板的抗弯性能及阻燃性能更优.  相似文献   

脱水对栓皮栎种子基因表达的影响     

李东兴  钱家连  许慧慧  张国伟  任俊杰  王茜  许洋  王利兵  于海燕  李迎超 《东北林业大学学报》2022,50(3):1-8

以收集于同一栓皮栎优良单株种子为试验材料,通过脱水和萌发试验确定脱水敏感关键时期,对未脱水(CK)和脱水敏感关键时期种子进行转录组测序分析,探究种子脱水过程中基因表达变化,挖掘与种子脱水敏感性相关的基因。结果表明：栓皮栎种子含水量与萌发率间呈极显著正相关。种子萌发临界含水量在28.20%(T2)左右,致死含水量在17.79%(T11)左右。通过差异基因表达分析,在比较组T2和CK,T11和T2和T11和CK中分别获得4 405、4 066和5 907个差异表达基因。这些差异表达基因分别被富集到生物学过程,分子功能和细胞组分3个功能类别以及内质网中蛋白质加工与植物激素信号传导等代谢通路中。其中,MYB108、MYB1R1、ERF1B、UNE10、CRF4、CML11、JAZ、MYC2、TGA等基因可能调控种子脱水过程中活性氧的产生与清除机制,以及胁迫信号的传导等过程,进而在种子对脱水的响应中发挥重要调控作用。  相似文献   

豚草和三裂叶豚草拮抗植物的筛选     

付开赟  王钿  丁新华  贾尊尊  吐尔逊·阿合买提  张国良  付卫东  文俊  加马力丁·吾拉扎汗  王兰  郭文超 《新疆农业科学》2022,59(12):3030-3046

【目的】 研究豚草(Ambrosia artemisiifolia L.)和三裂叶豚草(Ambrosia trifida L.)浸提液对常用替代牧草高羊茅、早熟禾、黑麦草、披碱草,以及对苜蓿、葵花、玉米、小麦、甜菜种子萌发的影响;筛选对豚草和三裂叶豚草具有防控效果的替代植物以及最佳混种方式。【方法】 采用培养皿滤纸法,研究豚草和三裂叶豚草浸提液对供试种子萌发的影响。采用盆栽竞争试验,运用DeWit取代试验研究法,设置牧草和入侵杂草5种混种方式,混种比例分别为1∶1、1∶2、1∶3、2∶1、3∶1,研究黑麦草、披碱草和高羊茅与豚草和三裂叶豚草的竞争效应,分析3种牧草对豚草和三裂叶豚草的替代控制潜力。【结果】 随着豚草和三裂叶豚草的浸提液浓度的增加,4种常用替代牧草种子和新源县5种主要作物种子发芽率,发芽指数和化感效应指数均下降。5种混种密度下,黑麦草、高羊茅与三裂叶豚草混种比例为3∶1时,三裂叶豚草的竞争平衡指数分别为(-0.505 1±0.301 5)、(-0.757 6±0.265 88)均显著小于0(P<0.05);黑麦草、高羊茅与豚草混种比例为1:3时豚草竞争平衡指数分别为(-0.955 8±0.518 08)、(-2.049 7±0.178 55)均显著小于0(P<0.05)。【结论】 豚草和三裂叶豚草浸提液对供试种子萌发具有化感抑制作用;且浸提液浓度越大抑制作用越强,同时叶部化感抑制作用大于根部。三裂叶豚草对四种牧草种子萌发的化感抑制作用大于豚草。黑麦草和高羊茅可以作为豚草和三裂叶豚草的替代植物。黑麦草和高羊茅防治三裂叶豚草时建议播种比例为3∶1;防治豚草时建议播种比例为1∶3。豚草和三裂叶豚草发生密度较大时其化感抑制作用越强,影响牧草萌发生长,应适当加大替代牧草播种量。  相似文献   

Strangulation of the small intestine by an anomalous congenital band in a yearling     

A. C. O. Dearo  G. de Moraes Marcondes  J. C. O. Araújo  C. E. S. Grumadas  P. C. Marino  W. T. Teixeira  G. de La Penha Chiacchio Fernandes 《Equine Veterinary Education》2014,26(12):640-644

Strangulating obstruction of the small intestine by anomalous mesenteric bands is an uncommon cause of colic in horses. The most commonly reported bands are mesodiverticular bands that are embryological remnants of the vitelline arteries. Despite the congenital nature of the anomaly, a wide age range of horses can be affected. This report describes a case of small intestinal strangulating obstruction caused by an unusual, anomalous congenital band attached to the ileocaecal fold in a yearling colt. Information including case background, history, clinical, laboratory, surgical and pathological findings is described.  相似文献   

Benthic microbial indicators of fish farm impact in a coastal area of the Tyrrhenian Sea     

Tiziana La Rosa  Simone Mirto  Antonio Mazzola  Teresa Luciana Maugeri 《Aquaculture (Amsterdam, Netherlands)》2004,230(1-4):153-167

We studied the impact of organic loads due to the biodeposition of a fish farm in a non-impacted coastal area of the Tyrrhenian Sea (Western Mediterranean). Sediment chemistry and benthic microbial community were investigated from July 1997 to February 1998 on monthly basis at two stations: one was located under the fish farm, while the second was about 1 km away, and served as a reference site. The presence of the cage induced rapid changes in the benthic conditions: the sediments were rapidly (after 6 weeks) reduced. A significant accumulation of biopolymeric carbon was observed beneath the cage both 2 weeks after the initial cage deployment, on non-impacted sediments, and 5–7 months after, and appeared to be related to the fish farm production cycle. The density of microbial communities beneath the fish farm increased only during the first month of farming activity (July) and partially 7 months after cage disposal (i.e. in January), when there was a significant sediment organic enrichment. Additional evidence of rapid impact of the fish farm on the benthic bacterial communities is provided by the increase in the numbers of autofluorescent microbial cells. The photosynthetic eukaryotic cells displayed a highly reduced contribution to total autofluorescent microbial density, indicating that their decrease is related with biopolymeric carbon accumulation, and probably was due also to “shadow effect” induced by suspended material, coming from the fish farm, on the environment below. We propose here, to apply the ratio of culturable heterotrophic bacteria to microbial direct counts (CFU/MDC) to detect fish farm impact. In cage sediments, organic enrichment and the consequent modification of the characteristics of the benthic environment, determined an increase in aerobic heterotrophic bacteria and vibrio density indicating that they are efficient colonizers of organic-rich sediments. Densities of Escherichia coli and Enterococci were not significantly higher than in the reference site, and are likely of terrestrial origin. Thus they cannot be used as specific indicators of fish farm impact.  相似文献   

不同株型冬小麦冠层结构特征多时相分析   总被引：2，自引：1，他引：1  

杨贵军  邢著荣  黄文江  齐腊  李伟国 《农业工程学报》2010,26(7):227-234

同一株型不同生育期、不同株型相同生育期其结构参数均具有不同的变化特点,了解其变化,一方面有利于区分不同株型结构,进一步提高LAI（叶面积指数）等指标参数的遥感反演精度,另一方面可用于定量作物肥水管理,提高肥水利用效率。该文结合冬小麦整个生育期,在北京小汤山试验基地开展两期品种试验,对比分析实测冠层多角度光谱及结构参数,得出通过多角度光谱数据区分株型的最佳波段是红光波段,两期LAI与平均叶倾角(ALA)变化均表明,最佳时期为拔节期;起身期至拔节期所选试验品种均体现直立型品种LAI大于披散型品种。2009年试验表明利用J411 4月底LAI变化趋势差异也可较好的区分作物株型;披散型品种9428特征尺度变化出现“跷板”效应,可以作为株型识别的依据之一。  相似文献   

孑遗植物中华桫椤2个群体遗传多样性的ISSR分析     

李媛  侯可雷  应站明  宋国伟 《广西农业生物科学》2010,(4):679-684

为阐明小尺度范围内濒危物种孑遗植物中华桫椤种群的遗传多样性,保护和恢复种质资源,本文采用ISSR分子标记技术对云南屏边大围山的大围山红旗水库和大围山山谷2个中华桫椤种群的遗传多样性进行分析。结果表明用从100个随机引物中筛选出的20个能高产稳定扩增的ISSR引物对2个群体共57个样品进行扩增,共获得132个可分析位点,其中大围山红旗水库的多态性位点83个,占62.87%,而大围山山谷的多态性位点97个,多态位点百分率（P）为73.48%,两者Nei＇s基因多样性分别为0.2614和0.2832,Shannon＇s信息指数分别为0.3762和0.4135,两个种群的遗传分化系数Gst为0.0701,分析结果表明中华桫椤种群内的遗传多样性较高,但两种群间的遗传分化不明显。本研究结果将对中华桫椤自然群体的保育和管理具有重要意义。  相似文献   

院所两级科研成果信息数据库设计与实现     

许士东  马建荣  郭君  蒋国伟 《计算机与农业》2010,(6):43-44,88

通过运用信息系统和信息管理方法,结合院所两级科研管理的实际情况,利用当前流行的数据库管理技术,设计了院所两级科研成果信息数据库,提供了数据库设计、系统功能设计、网络体系结构等一系列的解决方案,并依托局域网平台实现了科研管理信息的网络化运行、数字化存储和科学规范化管理。  相似文献